Bacterial community composition of the Yellow Sea Cold Water Mass studied by PCR-denaturing gradient gel electrophoresis

Abstract

Bacterial community composition and predominant bacteria were analyzed by PCR-denaturing gradient gel electrophoresis (DGGE) in the Yellow Sea Cold Water Mass (YSCWM). The results analysed by Glyko Bandscan software showed that samples from all stations in April and stations in the YSCWM area in October had almost the same number of different DNA bands (17 and 16 respectively) with high diversity. However, samples from the stations out of YSCWM area had fewer DNA bands (about 12) with lower diversity. 24 DGGE bands reflecting varying phylotypes were excised, cloned and sequenced. Phylogenetic analysis of 24 cloned bands showed that bacterial phylotypes were made up of two phyla bacteria, Proteobacteria and Bacteroides. Among these sequences, 16 were related to γ-Proteobacteria and δ-Proteobacteria and 5 were related to Bacteroides. It indicated that bacterial community composition, as well as the predominant bacterial groups, from all sampling stations in April (the temperature of seawater was around 7-12°C) and the inter of YSCWM in October (≤ 10°C) was the same, different from the exterior of YSCWM (≥ 19°C). By comparing, from samples of exterior of YSCWM, the predominant bacteria groups were different with the different sampling stations. So it suggested that bacterial community composition and the characteristic of predominant bacteria of the YSCWM may have something to do with the development of the YSCWM.